diff options
author | yar <yar@FreeBSD.org> | 2007-10-31 08:20:09 +0000 |
---|---|---|
committer | yar <yar@FreeBSD.org> | 2007-10-31 08:20:09 +0000 |
commit | 402e21e0f95128bd4e5b0e8500ff91b5d832e41c (patch) | |
tree | 5181e118155463cd6b40f8effdbfaa8551425e49 /usr.bin/make | |
parent | 84c802e0f211ac41c5fea945a6a2502dfdb12660 (diff) | |
download | FreeBSD-src-402e21e0f95128bd4e5b0e8500ff91b5d832e41c.zip FreeBSD-src-402e21e0f95128bd4e5b0e8500ff91b5d832e41c.tar.gz |
Give more details on the following topics:
o How global, command-line, and environment variables relate.
o What peculiarities the -f option has WRT ${MAKEFLAGS}.
Diffstat (limited to 'usr.bin/make')
-rw-r--r-- | usr.bin/make/make.1 | 84 |
1 files changed, 77 insertions, 7 deletions
diff --git a/usr.bin/make/make.1 b/usr.bin/make/make.1 index b226f83..80d2496 100644 --- a/usr.bin/make/make.1 +++ b/usr.bin/make/make.1 @@ -198,6 +198,13 @@ Multiple .Fl f options can be supplied, and the makefiles will be read in that order. +Unlike the other command-line options, +.Fl f +is neither stored in +.Va .MAKEFLAGS +nor pushed down to sub-makes via +.Ev MAKEFLAGS . +See below for more details on these variables. .It Fl I Ar directory Specify a directory in which to search for makefiles and included makefiles. Multiple @@ -466,7 +473,21 @@ environment variable or the target. .It Local variables Variables that are defined specific to a certain target. -The seven local variables are as follows: +.El +.Pp +If the name of an environment variable appears in a makefile +on the left-hand side of an assignment, +a global variable with the same name is created, and the latter +shadows the former as per their relative precedences. +The environment is not changed in this case, and the change +is not exported to programs executed by +.Nm . +However, a command-line variable actually replaces +the environment variable of the same name if the latter exists, +which is visible to child programs. +.Pp +There are seven local variables in +.Nm : .Bl -tag -width ".ARCHIVE" .It Va .ALLSRC The list of all sources for this target; also known as @@ -528,7 +549,6 @@ These variables are .Va .ARCHIVE , and .Va .MEMBER . -.El .Pp In addition, .Nm @@ -631,14 +651,19 @@ The environment variable may contain anything that may be specified on .Nm Ns 's -command line. +command line, +including +.Fl f +option(s). Its contents are stored in .Nm Ns 's .Va .MAKEFLAGS variable. All options and variable assignments specified on .Nm Ns 's -command line are appended to the +command line, except for +.Fl f , +are appended to the .Va .MAKEFLAGS variable which is then entered into the environment as @@ -646,16 +671,61 @@ entered into the environment as for all programs which .Nm executes. +.Pp By modifying the contents of the .Va .MAKEFLAGS -variable, makefile can alter the contents of the -.Va MAKEFLAGS +variable, a makefile can alter the contents of the +.Ev MAKEFLAGS environment variable made available for all programs which .Nm -executes; compare with the +executes. +(This includes adding or modifying +.Fl f +option(s).) +Note that any options entered to +.Va .MAKEFLAGS +neither affect the current instance of +.Nm +nor show up in its own copy of +.Ev MAKEFLAGS +instantly. +However, they do show up in the +.Ev MAKEFLAGS +environment variable of programs executed by +.Nm . +On the other hand, a direct assignment to +.Ev MAKEFLAGS +neither affects the current instance of +.Nm +nor is passed down to +.Nm Ns 's +children. +Compare with the .Ic .MAKEFLAGS special target below. .Pp +To sum up what was said on +.Fl f , +it can appear in +.Va .MAKEFLAGS +and affect the current +.Nm +at the same time only if inherited from +.Ev MAKEFLAGS +in +.Nm Ns 's +initial environment. +On the other hand, a +.Fl f +option from +.Nm Ns 's +command line +does affect +.Nm , +but it is never transferred to +.Va .MAKEFLAGS +or further. +.Pp When passing macro definitions and flag arguments in the .Ev MAKEFLAGS environment variable, |